Off-peak water heating system



Dec. 16, 1941. H. M. BIEBEL OFF-PEAK WATER HEATING SYSTEM Filed March 3l, 1941 INVENTOR. HERMA /v 5D/55a JW Y A TTORNE Y.

Patented Dec. 16, 1941 OFF-PEAK WATER. HEATING SYSTEM Herman M. Biebel, Elgin, Ill., asslgnor to McGraw Electric Company, Elgin, lll., a corporation of Delaware Application March 31, 1941, Serial No. 385,979

` Claims.

My invention relates to electric heating systems and particularlyto off-peak water heating systems.

The main object of my invention is to provide a relatively simple and inexpensive control means for a water heating system that will delay the start of the energization of the heater for a time after the start of an off-peak period, which length of time increases with the amount of hot water in the tank at that time.

Other objects of my invention will either be apparent from a description of one form ernbodying m; invention or will be specifically pointed out in the course of such description and set forth in the appended claims.

In the single sheet of drawings,

Figure 1 is a view showing the elements constituting the cooperating parts of my system as associated with an ordinary domestic hot water tank, the latter being shown in vertical section,

Fig. 2 is a fragmentary view of one part of the elements utilized in my system shown at the l start of a heating operation,

Fig. 3 is a fragmentary view showing certain of the control parts just before the end of a heating operation, and,

. provided with two peripherally spaced arms 45 Fig. 4 is a fragmentary view showing certain of the control parts just after the end of a heating operation.

Referring first to Fig. l of the drawing, I have there shown the usual domestic hot water tank I provided with a cold water inlet pipe I3 and a hot water outlet pipe l5 connected to the tank in the usual manner. I may provide a mass I1 of heat insulating material around the tank which may be protected and held in proper operative position by an outer casing i9, all in a manner well known in the art. I provide further an electric heating element 2| which may be so designed and constructed as to be secured around the outside of the tank and which may be located in a tunnel member 23. While I have shown an outside heating element I do not desire to be limited thereto since the control system more particularly embodying my invention can be operatively associated with any other kind of electric tank heater.

I provide a continuously operative timing means designated generally by the numeral 25 and including an electric motor 21 which is connected to two supply circuit conductors 29 and 3| so that it may operate continuously. I provide a worm gear 33 on the shaft of the motor which worm gear is adapted to mesh with and drive a worm wheel 35.

here that I have illustrated this continuously operative timing-means generally only but I desire to provide a driving means of any kind which will cause rotation of either the worm wheel 35 or a shaft 31 through one complete revolution in I desire to point out and 41 for a purpose which will hereinafter appear.

I provide a pair of fixed contact members 49 and 5| spacedly mounted on the outer end of the arm 39 in a position to be engaged by the contact blade 4|, as will be hereinafter set forth. The parts 4|, 49 and 5| constitute an on and off switch.

The two fixed Contact members 4 9 and 5I are connected with a pair of slip rings 53 and 55 insulatedly mounted on shaft 31, by conductors 51 and 59. I wish to point out that while conductors 51 and |59V are shown as apparently extending from the contact members to the slip rings disassociated from the arm 39 and the shaft 31, they will be supported by shaft 31 and arm 39 to rotate therewith, all in a manner well known in the electrical -art relating to such structures.

Means for causing closing of the switch comprising the parts 4|, 49 and 5| may include a pin 6| carried on an arm 63 to extend substantially parallel with the shaft 31. Arm 63 may be supported by a bushing 65 movably mounted on shaft 31. I have illustrated a support 61 for one end of shaft 31 but do not desire to be limited thereto. A thermally responsive member in the form of a rod 69 has its upper end fixedly held by a bracket 1| which bracket is supported by the upper end of the tank Il. While I have shown a bar or rod 69 of non-expansible material, it is obvious that I may use an expansible rod with but slight changes in the control structure. The lower end of bar G9 may be provided with teeth adapted to mesh with teeth on the one end of the bushing 65. If it be assumed that the rod 69 is made of some substantially non-expansible material, when subjected to increase of temperature, the upper end of rod 69 will be moved upwardly in accordance with the expansion of the tank Il when filled with hot water. It is, therefore, evident that arm 63 will be caused to turn in a clockwise direction and it may be assumed, for illustrative purposes, that arm 63 and pin 6| will be moved to the posit1ons shown in the broken lines in Fig. 1 when the tank contains a predetermined quantity of hot water Which may be on the order of one-third or one-half of its entire contents. The rod 69 may be said to respond to the average temperature of the water in the tank or 'to its heat condition or its heat content.

I provide a thermal heater control switch 13 which is in heat-receiving relation with the lower end portion of the tank I| and is to be understood as being adapted to cause deenergization of the heater 2| when the tank is substantially full of hot water. Switch 13 includes a bimetal bar 15 having one end fiXedly mounted, say on the tank, while the free end of bimetal bar 15 may Vengage with and move away from a fixed contact member 11.

I provide further an electromagnetic heater control switch including a coil 19 adapted to magnetize a movable core 8|. This core is connected to an upper main contact bridging member 83 and a lower auxiliary bridging member 85 adapted, respectively, to engage with and be disengaged i'rom fixed contact members 81 and 89.

The supply circuit conductor 29 is connected by a conductor 9| with one of the fixed contact' members 81, the other xed contact member 81 being connected by a conductor 93 with one terminal of heater 2|. The other terminal of heater 2| is connected to the fixed end of bimetal bar 15. Contact member 11 of switch 13 is connected by a conductor 95 with the other supply circuit conductor 3 I A conductor 91 connects supply circuit conductor 29 with a conductor 99 ending at a contact arm in engagement with slip ring 53. The other slip ring 55 is engaged by a contact arm |03 connected by conductors |05 and |01 with one terminal of coil 19. The other terminal of coil 19 is connected by a conductor |09 with that terminal of heater 2| connected to one terminal of the thermal switch13.

Let it be assumed that the tank I| has just been filled with cold water and that the position of switch-actuating pin 6| is that shown in full lines in Fig. 1 of the drawing. The continuously operative timer may be considered to be shown in the4 position which it would normally occupy just before the start of an off-peak period and, for illustrative purposes, it may be stated that an o-peak period may have a duration of eight hours and extend from 10 p. m. to 6 a. m. As will be hereinafter' set forth, it is possible to start operaion of the heater at any time of day and it is to be understood that the positions of the continuously operative timer in which they are shown in Fig. 1 of the drawing, may be obtained, for initial use of the system, at any time of the day.

When arm 39 is caused to move in a clockwise direction, as hereinbefore set forth, arm will engage the end of pin 8| and thereby cause turning movement of arms 45, 41 and 4| on pin 43 until arm 4| has been moved int:l engagement with fixed contact members 49 and 5I, as is shown in Fig. 2 of the drawing. This will cause ener gization of coil 19 through the following circuit: Fromsup'piy circuit conductor 29 through conductors 91 and 99, contact arm IOI, slip ring 53, conductor 51 through engaged contact members 49, 4I and 5|, throughconductor 59, slip ring 55 and contact bar or brush |03, through conductors |05 and |01 to and through coil 19,

through conductor |09, the closed thermal switch 13 and from there through conductor 95 to the other supply circuit conductor 3|. This will cause energization of core 8| with attendant upward movement of the two contact bridging members, contact bridging member 83 being moved into engagement with fixed contact members 81 to close an energizing circuit through the heater substantially as follows: From supply circuit conductor 29 and conductor 9| to and through engaged contact members 81 and 83, through conductor 93 and heater 2l, through closed thermal switch 13 and from there through conductor 95 to the other supply circuit conductor 3|. Energization of heater 2| will therefore be effected and heating of the Water in the tankv will start.

A holding circuit for maintaining the electromagnetic switch in closed position is also eiected, this circuit being substantially as follows: From supply circuit conductor 29 through conductors 9| and to and through the engaged contact members 89 and 85, through a conductor H3 to that end of the coil to which conductor |01 is connected, through coil 19, conductor |09, switch 13 and from there through conductor 95 to the other supply circuit conductor 3|.

It is evident that the design, construction and adjustment of the component parts, particularly of the continuously operative timer, may be made such that when the tank contains a predetermined amount of cold water the thermally adjustable actuating pin 6| will be in position so that the relay energizing switch continuously moved by the timer may be closed at substan tially the start of an ofi-peak period but will be closed later if the tank contains a lesser quantity of cold water, the primary object being to start energization of the heater and heating of the water in the tank at a time which will cause substantially all of the water in the tank to be hot `iust'before the end of an o-peak period.

It is, of course, necessary that engagement of arm 4| with contact members 49 and 5| be broken at a time corresponding generally to the end of an off-peak period in order that the system may be ready to operate similarly at either the start of the next ofi-peak period or with a time delay, as set forth above. For this purpose I provide a pin ||5 which is shown generally only in the various figures of the drawing but is to be understood as being properly supported to be engaged by arm 41 hereinbefore described. Fig. 3 shows the position occupied by certain parts of my control system just before the end of an offpeak period when arm 41 on its supporting arm 39 has been moved almost into engagement with fixed pin l5. Fig. 4 shows the positions of these parts when arm 41 has been moved into engagement with fixed pin ||5 and has caused disengagement of contact arm 4| from the xed contact members 49 and 5|.

In case all of' the water in the tank has been heated to a desired temperature, that is, substantially all of the Water in the tank is hot, bimetal bar 15 will have iiexed to move its free end away from the fixed contact member 11 which would also have interrupted the hereinbefore described holding circuit for the electromagnetic switch. Movement of contact arm 4| away from contacts 49 and 5| would, therefore, reset the continuously movable switch including more particularly the contact arm 4|, so that at some later time, say at the start of the next off-peak period, the system would be ready to cause reenergization of the heater 2 I.

I provide a manually operable push button switch I|1 which may be located at any convenient place in the basement 0r one of the rooms of a home to be operated manually by for hot water.

the user of a water heating system of this kind to cause energization of the heater irrespective of the timing means. Such a condition may occur in case of sudden unexpected demands The iixed contact members H9 and |2| of the push button switch H1 are connected to conductors 99 and |05 respectively. A contact bridging member |23 may be normally moved into engagement with the fixed contact members Ii9 and I2I and the hereinbefore described energizing circuit through coil 1.9 will be effected although the contact bars 10i and |03 and the slip rings and the conductors to the ilxed contact members to the continuously movable switch will not be in electric circuit as hereinbefore described. l

Should it happen that all of the water in the tank is hot an appreciable length of time before the end of an oir-peak period and that bimetal bar flexed out of engagement with ilxed contact member 11, as hereinbefore described, and that withdrawal of some of the hot water occurred before the end of an oil-peak period, the coil 19 would be energized as hereinbeforeV described, with attendant reenergization of the heater 2| and heating of the water would again occur. described i'or the coil 19 ls independent of the on and olf switch moved continuously by the timer and is dependent only on the engagement of bimetal bar 15 with contact 11. Should it, therefore, occur that a, relatively large amount of hot water is withdrawn from the tank just before the end of an oiI-peak period, at which time contact bar Il is moved out of engagement with contacts I9 and 5I, reenergization of the heater will have been eiected as above described,

'and such reenergizatlon of the heater will continue until substantially all oi' the water in the tank is hot when flexing of bimetal bar 15 out oi' engagement with contact 11 will open the holding circuit of coll 19 of the contactor so that my system ls independent of the position of the timer-actuated Switch initiating the operation, under the conditions set forth above.

I desire to point out that the elements shown in the various ngures of the drawing are shown generally only and that all variations in design and construction may be made to provide a properly operative device giving the results hereinbefore set forth. All such modifications clearly coming within the scope of the appended claims are to be considered as being covered thereby.

I claim as my invention:

l. An oil-peak water heating system for a tank having an electric heater, comprising a continu- The holding circuit hereinbei'ore ously operative timer, a switch controlling the energizatlon of said electric heater adapted to be moved continuously by said timer in a given direction in a given path, a member in said path for actuating said switch from open to closed position, a thermal means on said tank responsive to the average tank water temperature adapted to move said switch-actuating member to engage said switch earlier in case the tank water temperature is low than ln case it is high and a fixed member in said path for moving said switch to ofi.' position. 1 l

2. An off-peak water heating system for a tank having an electric heater, comprising means including an electromagnetic switch for controlling the energization of said heater, a continuously operative timer, an on-and-o.' switch adapted to be moved continuously in a given direction in a circular path by said timer and effective to control the energization of said electromagnetic switch, a pin in said path for moving said timeractuated switch into closed position to cause energization of said electromagnetic switch and of said electric heater in case less than all oi' the water in the tank is hot and means responsive to the heat content of the tank for moving said pin.

3. In an off-peak water heating system for a tank having an electric heater, an electromagnetic switch for controlling the energization of said heater, a continuously operative timer, an on-and-off switch adapted to be moved continuously in a given direction in a circular path by said timer and effective to control the energlzation of said electromagnetic switch, a pin in said path for moving said timer-actuated switch into closed position to cause energization of said electromagnetic switch and of said electric heater in case less than all of the water in the tank ls hot, means responsive to the heat content of the tank for moving said pin and a thermallyactuable switch in the heater circuit for causing deenergizatlon of said heater when substantially all of the water in the tank is hot.

4. In an oir-peak water heating system for a tank having an electric heater, an electromagnetic switch and a thermally-actuable switch electrically connected in series circuit with each other and controlling severally the energization of the electric heater, an on-and-of! switch for controlling the energization of said electromagnetic switch, a continuously operative timer adapted to move said on-and-oi! switch continuously in a given direction in a given path, means movable in a part of said path to a position depending on the amount of hot water in the tank to cause movement of said on-and-oi! switch into on position earlier in case the average tank water temperature is low thanin case it is high and means having a ilxed position in said path to cause movement oi' said on-and-oi'! switch into ofi' position, to cause energization of said electric heater after a given delay after the start oi' an off-peak period in case the average temperature of the water in the tank is above a predetermined average value, to cause deenergization of said heater when the average temperature of the water in the tank is above a higher predetermined average value, to cause reenergization of said heater in case withdrawal of hot water during the rest' of an oil-peak period causes a. reduction of the average water temperature to below said first named predetermined value and to cause deenergization of said heater when the average temperature of the water in the tankls above said higher predetermined average value irrespective o1' the position oi' said on-and-oi switch.

5. A system as set forth in claim 2 and includlng a normally open switch operable into momentarily closed position to cause energization of said electromagnetic switch and oi' said heater at any desired time during an on-peak period in case less than al1 of the water in the tank is hot, said energization of the heater continuing until substantially all of the water in the' tank is hot. f

HERMAN M. BIEBEL. 

